Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

Abstract

Various metal-β zeolites have been synthesized under similar ion-exchange conditions. During the exchange process, the nature and acid strength of the used cations modified the composition and textural properties as well as the Brönsted and Lewis acidity of the final materials. Zeolites exchanged with divalent cations showed a clear decrease of their surface Brönsted acidity and an increase of their Lewis acidity. All materials were active as catalysts for the transformation of acetone into hydrocarbons. Although the protonic zeolite was the most active in the acetone conversion (96.8% conversion), the metal-exchanged zeolites showed varied selectivities towards different products of the reaction. In particular, we found the Cu-β to have a considerable selectivity towards the production of isobutene from acetone (over 31% yield compared to 7.5% of the protonic zeolite). We propose different reactions mechanisms in order to explain the final product distributions.

Isobutene from Ethanol: Describing the Synergy between In2O3 and m‐ZrO2

“…Sum et al . and other authors proposed that acetone condensation generates isobutene and acetates species or acetic acid, respectively. Our results suggest that acetaldehyde is a by‐product of the isobutene synthesis.…”

Renewable Gasoline Produced by Co-Cracking of Methanol and Ketones in Bio-Oil

“…Similar to the decarboxylation mechanism for acetone cracking (Cruz-Cabeza et al 2012), CPO and HPO could undergo aldol condensation and subsequent cracking to produce olefins and carboxylic acids, and then the carboxylic acids intermediates underwent decarboxylation to release CO 2 . The decarbonylation of ketones might mainly involve the direct rupture of C-C bonds to form small hydrocarbon fragments and released CO .…”

Size-Controlled Synthesis of Nano-Zeolites and Their Application to Light Olefin Synthesis

“…The relation between the pore sizes of zeolites and these intermediates are summarized in Table 2. Since trimers of acetone (pholone and iso-pholone) can be formed in beta zeolite (BEA zeolite, 12-membered rings), isobutylene and aromatics are observed as major products [39,88], where cyclic compounds of iso-pholone can be formed within the micropore of beta zeolite and converted into aromatics. When using ZSM-5 (MFI zeolite, 10-membered rings), isobutylene is formed within the crystal pore by decomposition of diacetone alcohol (dimer), not by decomposition of an acetone trimer (pholone and iso-pholone), due to spatial limitations of the MFI zeolite (10-membered rings) [25,26].…”